HR: 1400h
AN: G43B-13    [Abstracts]
TI: InSAR derived horizontal subsidence gradient as a tool for hazard assessment in urban areas.
AU: * Cabral-Cano, E
EM: ecabral@igeofcu.unam.mx
AF: Departamento de Geomagnetismo y Exploracion, Instituto de Geofisica, Universidad Nacional Autonoma de Mexico., Ciudad Universitaria, Del. Coyoacan, Mexico, DF 04510, Mexico
AU: Dixon, T
EM: tdixon@rsmas.miami.edu
AF: Rosenstiel School of Marine and Atmospheric Sciences, University of Miami., 4600 Rickenbacker Cswy., Miami, FL 33149, United States
AU: Diaz-Molina, O
EM: oscard@tonatiuh.igeofcu.unam.mx
AF: Departamento de Geomagnetismo y Exploracion, Instituto de Geofisica, Universidad Nacional Autonoma de Mexico., Ciudad Universitaria, Del. Coyoacan, Mexico, DF 04510, Mexico
AB: Mexico City's subsidence has been recognized for over a century, after the first well battery was drilled to supply water to the rapidly growing city at the end of the XIX century. Consequences of the subsidence process are costly but the economic consequences of subsidence in urban areas is hard to assess due to the fact that their costs are generally factored into yearly maintenance budgets rather than accounting for them as a unique natural disaster. It has thus become increasingly important to assess the extent and magnitude of damage due to ground subsidence in the Mexico City metropolitan area. Periodic InSAR and GPS measurements including data from an 8 site permanent GPS network in Mexico City has enabled us to derive an integrated composite displacement map for Mexico City. This image was used to calculate the horizontal subsidence gradient for areas smaller than 100x100m throughout the city by computing the observed displacement difference divided by the respective pixel to pixel horizontal distance and comparing similarly calculated values from all adjacent pixels in order to select the maximum gradient. Both empiric and analytical approaches can been used to correlate the potential for surface faulting in high horizontal subsidence gradient zones and show that the principal factor for constraining these areas can be successfully determined using a combined Differential InSAR and GPS approach. We present surface faulting risk maps for several cities in central Mexico derived from the horizontal subsidence gradient approach as an example of this technique.
DE: 1211 Non-tectonic deformation
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 1295 Integrations of techniques
SC: Geodesy [G]
MN: 2007 Joint Assembly